University of Northern Iowa UNI ScholarWorks Dissertations and Theses @ UNI Student Work 1991 Multivariate analysis of the Carex brevior group in Iowa Scott C. Zager University of Northern Iowa Let us know how access to this document benefits ouy Copyright ©1991 Scott C. Zager Follow this and additional works at: https://scholarworks.uni.edu/etd Part of the Biology Commons, and the Botany Commons Recommended Citation Zager, Scott C., "Multivariate analysis of the Carex brevior group in Iowa" (1991). Dissertations and Theses @ UNI. 181. https://scholarworks.uni.edu/etd/181 This Open Access Thesis is brought to you for free and open access by the Student Work at UNI ScholarWorks. It has been accepted for inclusion in Dissertations and Theses @ UNI by an authorized administrator of UNI ScholarWorks. For more information, please contact [email protected]. -- MULTIVARIATE ANALYSIS OF THE CAREX BREVIOR GROUP IN IOWA An Abstract of a Thesis Submitted In Partial Fulfillment of the Requirements for the Degree Master of Arts Scott C. Zager University of Northern Iowa December 1991 LI BRARY UNIVERSITY OF NORTHERN IOWA CEDAR FALLS, IOWA ABSTRACf In Iowa, the most troublesome sedges to identify are Carex brevior, .,C. festucacea, ..C. molesta, ..C. normalis, ..C. tenera, and ..C. tenera var. echinodes. These taxa form the _c. brevior group--part of an even larger aggregate of species associated with _c. straminea. Their morphological features are indistinct and intergrade into one another. Botanists have had difficulty classifying members of this aggregate for nearly 200 years. Some authors have viewed the taxa as separate species, others as polymorphic forms of a single species. Much of the contention has centered upon the variation of taxonomic characters used to delimit and distinguish species. The objectives of my study were: 1) to randomly sample up to 30 specimens from each population, at several populations of each taxa, to obtain statistical parameters for morphological characters and ascertain if variation occurs within populations, between populations, and between taxa; 2) to evaluate 44 characters and 12 character ratios for each taxa by Univariate Analysis and Stepwise Discriminant Analysis (SDA) and obtain reliable taxonomic characters or character combinations; and 3) to test the validity of taxonomic classifications within the _c. brevior group by determining if the morphological forms are significantly different using Canonical Discriminant Analysis (CDA). There were 450 samples collected at 15 sites (21 populations). The taxa were mostly found in different micro-habitats. Most character means were significantly different (l! < 0.0001), e.g., means of _c. molesta and _c. brevior were significantly different for 52 of the 56 characters tested. However, single characters could not reliably separate taxa because of overlapping ranges of variation. CDA revealed taxa to be significantly different (F = 24.08; ~ < 0.0001) along 4 canonical axes. SDA identified character combinations or suites which could reliably delimit and distinguish taxa. There were no subgroups observed within the taxa. Most of the variation expressed by each taxon was found within populations and there were few differences between populations. The characters varied in predictable patterns and this variation is mostly attributed to phenotypic plasticity. However, specimens were found at sympatric sites with unusual character states or mixed character suites, suggesting they are putative hybrids. .,:)..2 T - I '1 MULTIVARIATE ANALYSIS OF THE CAREX BREVIOR GROUP IN IOWA A Thesis Submitted In Partial Fulfillment of the Requirements for the Degree Master of Arts Scott C. _?,ager University of Northern Iowa December 1991 LIBRARY UNIVERSITY OF NOf:THE RN IOWA CEDAR FALLS, IOWA ii This Study by: Scott C. Zager Entitled: MULTIVARIATE ANALYSIS OF THE CAREX BREVIOR GROUP IN IOWA has been approved as meeting the thesis requirement for the Degree of Master of Arts. ~~"'I Date Dr. Lawrence J. Eilers, Chair, Thesis Committee '1/.zsJ; Date Dr. Daryl D. Smith, Member, Thesis Committee Y/10! ~ Date Dr. JaneL. Kotenko, Member, Thesis Committee 1/ti~( Date (2 -20-(l Date Dr. John W. Somervill, Dean, Graduate College ·· -\~~ "··-- -- , 1,..1., ~ t.lV f::,: ~ '.,.' . ~. : i~:. 1, ,'""'t ~" ( '""' 'lf~r ~·rr~):1Y {~F r· :C~t~T:·~~·f~ 1 ·~~ 10\~]i i r:r:i:.t;:. f\~ F;'.Li.::;. tf)V~·' :j lll ACKNOWLEDGEMENTS I have the privilege of being Dr. Lawrence J. Eilers' last graduate student; an honor he bestowed upon me for two years after his retirement. Mere words cannot express the magnitude of my gratitude nor my appreciation for his allowing me to perform this study under his direction. While primarily a floristic botanist, he has supervised my study with great insight, always focusing my thoughts toward the principles of good scientific research. He has been a true mentor in every sense. If this study has any significance, it is because he has disciplined my thoughts. If it has any error, it is because he would not restrain my enthusiasm. He has been a leader in preserving Iowa's diminishing natural areas, but he has expressed that his most cherished legacy is the students he has encouraged to become botanists, ecologists and conservationists. I was also fortunate to have assistance from Dr. Kay Klier, a plant taxonomist, whose career I predict will be equally as rewarding to the students she instructs. I wish to express my gratitude to my committee members Dr. Jane Kotenko and Dr. Paul Christiansen. I especially wish to thank Dr. Daryl Smith who gave me the opportunity to study at the University of Northern Iowa. All are individuals which I greatly admire. I wish to thank other University of Northern Iowa faculty: Dr. P. Whitson, Dr. 0. Schwartz, Dr. A Orr and Dr. J. Trainer. I wish to acknowledge The Iowa Academy of Science for funding travel expenses during this study. I also wish to thank Donna Ware and the Delzie Demaree Travel Award Committee for the opportunity to visit the Missouri iv Botanical Gardens. I wish to thank the College of Natural Sciences, University of Northern Iowa, for the Lantz Fellowship Award which enabled me to initiate this study. I wish to thank all the curators for loans, especially Dr. P. Holmgren (NY) and A E. Schuyler (PH) for their hospitality. Also, I wish to thank Dr. C. Reimers for his assistance in Philadelphia. I gratefully acknowledge Dr. P. Rothrock for his correspondence and assistance in identifying important taxa. I deeply appreciate Dr. A A Reznicek for his clarification of Carex straminea. Other individuals I wish to thank include Mark Leoschke, Barbara Wilson and John Nehnevaj for field assistance. I wish to thank AI Ehley, and the Roadside Assistance Office for a place to write. I wish to thank the Iowa Department of Natural Resources for permission to collect in State Parks and the Iowa State Preserves Advisory Board for permission to collect on Iowa preserves. More thanks to The Iowa Nature Conservancy for reviewing my study and permission to visit their preserves, and the Iowa-Illinois Gas and Electric Company for permission to visit Big Sand Mound Preserve. Finally, I would like to express my special appreciation to my wife Patty Vander Waal, without whose patience, love, and sacrifice this study would not have been possible. I wish also to thank my parents for their encouragement and support, especially my father who recognized that the world needs good biologists. v TABLE OF CONTENTS ACKNOWLEDGEMENTS . i i i LIST OF TABLES . X LIST OF FIGURES ... xii CHAPTER I. INTRODUCTION . 1 Statement of Problem .. 2 Taxonomic Classifications. 6 The Genus Carex ...... 6 Morpho 1ogy . 6 Subgeneric classifications .... 7 The Subgenera of Carex . 9 The Section Ovales Kunth ...... 10 The Subsection Festucaceae Mackenzie (nomina nuda}. 11 The Carex brevior Group. 11 The Taxonomic History of the Carex brevior Group . 13 Taxonomy of Carex straminea. 14 Taxonomy of Carex brevior. 16 Taxonomy of Carex tenera . 17 Taxonomy of Carex tenera var. echinodes. 18 Taxonomy of Carex festucacea . 18 Taxonomy of Carex normalis .... 19 Taxonomy of Carex molesta 20 Carex Evolution, Morphology and Genetics . 20 Phylogenetic Development of the Inflorescence. 20 vi Phenotypic Plasticity and Meristematic Development ... 24 Genetics ........ 26 Cytotogenetics ... 26 Agmatoploidy. 26 Hybridization ... 28 Population genetics of species aggregates. 30 Genetics of the Carex brevior group. 31 Summary of Literature. 32 CHAPTER 2. METHODS ...... 33 Herbarium Study. 33 Field Collections ........ 34 Laboratory Evaluation .... 36 Statistical Analyses .... 36 Univariate Analyses .. 36 Multivariate Analyses ... 40 CHAPTER 3. RESULTS ............. 45 Field Observations .. 45 Growth Habit of Iowa Ovales 45 Ecological Characteristics . 49 Field observations of ~. brevior .. 50 Field observations of ~. molesta . 50 Field observations of ~. festucacea ... 52 Field observations of ~. tenera. 52 vii Field observations of~. normalis •. 53 Field observations of ~. tenera var. echinodes . 54 Statistical Analyses ...... 55 Univariate Analyses ...... 55 Test of normality. 55 Infraspecific variation .. 78 Univariate tests of taxonomic significance 78 Multivariate Analyses. 79 Multivariate tests of taxonomic significance . 79 Infraspecific variation .. 81 Taxonomic Characters ..... 81 Stepwise Discriminant Analysis 89 Morphological Descriptions ... 91 Carex molesta .. 92 Carex brevior ..... 93 Carex normalis ..... 96 Carex festucacea . 96 Carex tenera 96 Carex tenera var. echinodes. 97